Although overshadowed by elections in Greece and France, Italy's local election results, announced late on Monday evening, are nonetheless fascinating. They represent a massive victory for a comedian-turned-blogger-turned-activist called Beppe Grillo. For years, the round-faced, 63-year-old with thick grey hair has been shaking the cage of traditional politics: staging rallies, organising petitions and pleading for a clean-up of the country's notoriously murky politics. He's been a bit like an Italian Michael Moore – a passionate self-publicist who sees the world in black and white.

Until now, no one really took the comedian seriously. He was a stone in the shoe and nothing more. But his Cinque Stelle political movement has come from nowhere to win, in recent projections, almost 20% of the vote in the city of Parma almost 15% of the vote in Genova, Grillo's home city. The centre right, by contrast, stands to win between just 10% and 20% in those cities.

The other extraordinary story of the elections – in which 28 provincial capitals and almost 1,000 town councils have gone to the polls – occurred in Palermo. There, in the Sicilian capital, the centre-left and centre-right coalitions appear set to gain barely more than 30% of the vote between them. It's as if the Tories and Labour were to get less than one-third of all votes cast. And the clear winner in Palermo is another small party of protest, the Italy of Values party, led by Silvio Berlusconi's nemesis, Antonio Di Pietro. Like Grillo, Di Pietro – a former magistrate who spearheaded investigations into corruption in the 1990s – has long campaigned for an end to corruption in public life.

Unlike France and Greece, the election results can't really be read as a reaction against austerity measures. Since Italy currently has a "technocratic" government (a non-political coalition of managerial safe-hands), those dishing out austerity weren't facing the electorate anyway.

But what it is a reaction against is the continuing farce of corrupt politicians trousering huge sums of money. In recent weeks, the news has been full of allegations (and filmed evidence) of epic embezzlement by politicians in the Northern League, and there have been serious allegations about the probity of mainstream politicians like Francesco Rutelli and Roberto Formigoni. Not for the first time, the Italian electorate appears to be yearning for transparency, and Di Pietro and Grillo appear to be the main beneficiaries.

The centre-left coalition will doubtless declare itself happy about the results: in Genova, after all, their candidate Marco Doria (from the ancient noble family that gave Sampdoria football club half its name) appears to likely to win over 45% of the vote. A similar percentage is likely to be garnered in other, traditionally leftwing cities.

And yet there are circumstances that should temper any optimism amongst the leftwing parties: in many cities, the coalition between the Northern League and Berlusconi's Freedom Party broke down, meaning rightwing votes were split. That coalition has been the bedrock of all Berlusconi's victories down the years and, when the prize at stake is national, rather than local, government, they will almost certainly kiss and make up. And even in one city where the rightwing vote was split, Verona, the Northern League candidate seems likely to win well over 55% of the vote.

But the greatest reality check on any exuberance about a bright, new political dawn in Italy is the fact that Berlusconi, the slickest salesman on the peninsula, appears to have sat this one out. A master at picking the right fight, he's been almost entirely absent from campaigning this time round. It's almost as if he thought he should show the centre-right what it was missing, let them remember they're nothing without him. Had he been all channels blazing in this election, the results, there's no doubt, would have been very different.